The Post-Operative Ward Call: A Skill Almost Never Taught
As an F1, you will be bleeped about post-operative patients constantly — a patient who won't pass urine, one with a rising temperature, one with unexpected tachycardia. These calls are common, stressful, and frequently mismanaged because medical students are taught surgical pathology but rarely taught how to review a post-op patient systematically.
This guide gives you the framework to assess any post-operative patient confidently and recognise the complications that need urgent action.
The Timeline of Post-Operative Complications
The timing of a complication after surgery is one of the most important diagnostic clues. Complications follow a predictable temporal pattern:
| Timeframe | Typical complications |
|---|---|
| 0–4 hours (immediate) | Haemorrhage, airway compromise, hypothermia, inadequate analgesia, urinary retention from anaesthesia |
| 4–24 hours (early) | Reactionary haemorrhage (as BP recovers and clot dissolves), pulmonary atelectasis, pain crisis, nausea and vomiting, urinary retention |
| 1–3 days | Chest infection/pneumonia, urinary tract infection, ileus, early wound haematoma, DVT beginning |
| 3–7 days | Wound infection, anastomotic leak (abdominal surgery), DVT/PE, catheter-associated UTI |
| 7–30 days | Wound dehiscence, incisional hernia, late bleeding, adhesion obstruction |
🧠 Mnemonic
The 5 Ws of post-operative fever (the classic surgical teaching):
- Wind (Days 1–2): Atelectasis — collapse of lung segments due to shallow breathing, secretion retention, pain
- Water (Days 3–5): UTI — especially if catheterised
- Wound (Days 5–7): Surgical site infection
- Walking (Days 4–6): DVT/PE — deep vein thrombosis or pulmonary embolism
- Wonder drugs (any time): Drug fever — particularly beta-lactam antibiotics, heparin-induced thrombocytopenia
The Systematic Post-Operative Assessment
Approach every post-op ward call using the A-E framework, but contextualised to the surgical patient.
Before Arriving at the Bedside
Pull up the chart and answer these questions:
- 1What operation was performed? (Laparotomy? Orthopaedic? Vascular?) — this predicts likely complications
- 2How many hours/days post-op? — use the timeline above
- 3What are the current observations and how have they trended? — single abnormal obs less worrying than a downward trend
- 4What is the fluid balance? — total input vs output
- 5What drains are in situ and what is coming out? — bloody drain fluid suggests haemorrhage; bilious or faeculent fluid is alarming
- 6What medications are prescribed? — opioids (constipation, respiratory depression), NSAIDs (renal impairment, GI bleeding), antibiotics
A — Airway
Usually clear. In the immediate post-op period, check the patient is fully awake and protecting their airway — residual anaesthetic and opioids can compromise consciousness and airway reflexes.
B — Breathing
- Respiratory rate and oxygen saturations
- Listen to the lung bases — reduced air entry and dullness = atelectasis or pneumonia
- Ask: "Are you short of breath? Does it hurt to take a deep breath?" (pleuritic chest pain = PE or pneumonia)
- Check whether the patient is using supplemental oxygen and whether their requirement has increased
⚠️ Red Flag
New hypoxia in the first 24–72 hours post-op should raise concern for pulmonary atelectasis (most common), aspiration pneumonia, or pulmonary embolism. A PE can occur any time post-operatively but peaks at 5–14 days. New oxygen requirement or unexplained tachycardia in any post-op patient warrants a CTPA if PE is suspected.
C — Circulation
- Heart rate and blood pressure — both together, not in isolation (HR 110, BP 110/70 may be early haemorrhagic shock)
- Urine output: target ≥0.5 ml/kg/hour — less than this = oliguria, which is a key post-op warning sign
- Check drains: fresh bright red blood is arterial haemorrhage; old dark blood may be normal
- Check the wound: swelling, haematoma, ooze through the dressing
Shock in the post-op patient:
| Type | Signs | Cause |
|---|---|---|
| Haemorrhagic | Tachycardia, hypotension, low urine output, cool peripheries | Bleeding from operation site or vessel |
| Septic | Tachycardia, hypotension, fever, warm peripheries initially | Anastomotic leak, wound infection, chest |
| Cardiogenic | Hypotension, raised JVP, pulmonary oedema | MI precipitated by surgical stress |
| Anaphylactic | Urticaria, bronchospasm, hypotension | Drug reaction (antibiotics, latex) |
D — Disability
- GCS and pupil responses
- Blood glucose — diabetic patients are at risk of hypoglycaemia if nil by mouth, or hyperglycaemia from surgical stress
- Pain score — undertreated pain increases stress response, impairs deep breathing (promoting atelectasis), and prevents mobilisation (increasing DVT risk)
E — Exposure
- Examine the abdomen: tender? Rigid? Distended? (Distension + absent bowel sounds = ileus; peritonism = anastomotic leak or visceral perforation)
- Check wound: erythema, warmth, swelling, discharge (purulent = infection; straw-coloured = seroma; faeculent = fistula)
- Check calf: swelling, warmth, tenderness (DVT) — though clinical signs are unreliable; a low threshold for Doppler ultrasound
- Check all drain sites
Oliguria: The Most Common Post-Op Ward Call
Oliguria (urine output < 0.5 ml/kg/hour, or < 30 ml/hour in an average adult) is the most common reason you will be bleeped about a post-op patient. It must be taken seriously.
The Three Causes: Pre-Renal, Renal, Post-Renal
| Type | Cause | Investigation | Management |
|---|---|---|---|
| Pre-renal (most common) | Hypovolaemia (bleeding, inadequate fluids, third spacing) | U&Es, fluid balance, urine sodium < 20 | IV fluid bolus (250–500 ml crystalloid), reassess |
| Renal | Acute tubular necrosis (from prolonged hypotension, nephrotoxic drugs, contrast) | U&Es, urinalysis, rising creatinine | Remove nephrotoxins, careful fluid balance, renal review |
| Post-renal | Blocked catheter (most common!), ureteric injury | Flush or replace catheter; check for kinking | Unblock catheter first — takes 30 seconds and is often the answer |
💎 Clinical Pearl
Always check the catheter first — a kinked or blocked catheter is the commonest cause of apparent oliguria on surgical wards and takes 30 seconds to exclude. Pull back the sheet, check the tubing isn't kinked, flush the catheter with 20 ml saline. If that doesn't solve it, then investigate.
Fluid Challenge and Monitoring
If you suspect pre-renal oliguria:
- 1Give a crystalloid bolus: 250–500 ml sodium chloride 0.9% or Hartmann's over 15–30 minutes
- 2Reassess urine output after 30–60 minutes
- 3If no response, check U&Es for creatinine trend
- 4If urine output remains poor after two challenges, escalate — this patient may need a urinary catheter (if not already in situ), central venous pressure monitoring, or renal team input
Post-Operative Analgesia: The WHO Ladder Applied Surgically
Adequate analgesia is a clinical priority, not a comfort measure. Undertreated pain causes:
- Splinting (shallow breathing → atelectasis → pneumonia)
- Immobility (DVT, pressure sores)
- Stress response (hyperglycaemia, catabolism, poor wound healing)
- Urinary retention
| Step | Analgesia | Example |
|---|---|---|
| Step 1 | Regular paracetamol ± NSAID | Paracetamol 1g QDS + ibuprofen 400 mg TDS (if no contraindication) |
| Step 2 | Weak opioid | Codeine 30–60 mg QDS or tramadol |
| Step 3 | Strong opioid | Morphine IV/IM/SC PRN, PCA, epidural |
⚠️ Red Flag
NSAIDs post-operatively: Contraindicated in renal impairment (including pre-renal oliguria), peptic ulcer disease, bowel surgery (impaired anastomotic healing), and patients on anticoagulation. Paracetamol is the safest base analgesic. Always check renal function before prescribing NSAIDs.
Recognising the Anastomotic Leak
An anastomotic leak — breakdown of a surgical bowel join — is the most feared complication of abdominal surgery. It typically presents at days 4–7, but can occur any time.
Clinical features:
- Sudden deterioration in a patient who was previously improving
- Tachycardia (often the earliest sign)
- Fever and rigors
- Increasing abdominal pain and peritonism (tenderness, guarding, rigidity)
- Deteriorating drain output: purulent, bilious, or faeculent fluid
- Rising CRP, rising WCC, rising lactate
⚠️ Red Flag
Anastomotic leak is a surgical emergency. If you suspect it, call the surgical registrar immediately. Delayed recognition is the most common reason for death from this complication. "The patient who was getting better and is now getting worse" should always trigger anastomotic leak in the differential.
Common Examiner Follow-Up Questions
"You are called about a patient on day 2 following a right hemicolectomy who has a temperature of 38.4°C. Walk me through your assessment."
"I would perform an A-E assessment. Using the 5 Ws framework for post-operative fever on day 2: Wind is the most likely cause — atelectasis from shallow breathing post-op. I would check respiratory rate, oxygen saturations, and auscultate the chest. I'd request a chest X-ray and encourage deep breathing exercises and physiotherapy. Other causes to consider at day 2: UTI if catheterised (send a CSU), wound haematoma (examine the wound), and drug fever (check antibiotics prescribed). I would check FBC, CRP, blood cultures, urine culture, and wound swab if there is any discharge. The anastomotic site is not usually at risk until day 4–7, but I would examine the abdomen carefully and have a low threshold for escalation if there is any peritonism."
"What is an ileus and how do you manage it?"
"Post-operative ileus is a temporary paralysis of bowel motility following surgery, particularly abdominal operations. It is caused by the combination of peritoneal handling, opioid analgesia, electrolyte disturbance, and the stress response. Clinically: the patient has abdominal distension, no bowel sounds, nausea and vomiting, and is not passing flatus or stool. An erect chest X-ray and AXR confirm dilated loops of bowel. Management is supportive: nil by mouth until bowel sounds return, nasogastric tube on free drainage if vomiting, IV fluids to maintain hydration, correct electrolytes (especially potassium and magnesium), and minimise opioids where possible. Most ileus resolves within 3–5 days. If it persists beyond 5–7 days or is associated with new abdominal signs, consider anastomotic leak, closed loop obstruction, or adhesional obstruction — CT abdomen is warranted."
"A post-operative patient has a urine output of 15 ml/hour for the past 3 hours. They had a right hip replacement 18 hours ago and their blood pressure is 100/60. What do you do?"
"This patient has oliguria — less than 0.5 ml/kg/hour — combined with hypotension, suggesting hypovolaemia as the most likely cause. My first step is to check the catheter is not blocked or kinked. I would then review the fluid balance chart: total input vs output over the last 24 hours. If hypovolaemic, I would give a 500 ml crystalloid bolus of sodium chloride 0.9% or Hartmann's over 15–30 minutes and reassess. I would check U&Es, FBC, and a coagulation screen — after hip replacement, significant occult haematoma in the thigh can cause hypovolaemia. I would examine the wound and thigh for swelling. If urine output does not respond to two fluid challenges and blood pressure remains low, I would escalate to the surgical registrar for senior review and consider whether there is ongoing haemorrhage requiring re-exploration."